Gonorrhea is epidemic in the United States. The emergence of increasingly drug resistant gonococcal strains and the appearance of multiple resistance strains make it difficult to control the epidemic. We can isolate increasingly resistant strains by growing N. gonorrhoeae on sub-inhibitory concentrations of one antibiotic. But such strains are now resistant to other antibiotics. The objective of our proposed research is to study the genetic basis and the mechanism(s) of multiple drug resistance of clinical isolates and strains obtained from our in vitro experiment.